Journal of Paleontology; September 2008; v. 82; no. 5;
p. 1043-1050; DOI: 10.1666/07-101.1
© 2008 Paleontological Society
Permian Colonial Rugose Corals from the Wrangellian Terrane in Alaska
Calvin H. Stevens1
1 Department of Geology, San Jose State University, San Jose, California 95192-0102, <stevens@geosun.sjsu.edu>
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INTRODUCTION
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WRANGELLIA WAS one of the first described and probably the most widely known of the North American Cordilleran terranes. On the basis of Triassic stratigraphy (Jones et al., 1977) and paleomagnetism (Hillhouse, 1977), the name Wrangellia was proposed for large areas of outcrop in Alaska, British Columbia, and Oregon (Fig. 1).
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FIGURE 1—Areas (shaded) regarded as parts of Wrangellia by Jones et al. (1977)
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The most recent paleomagnetic data from the amalgamated Alexander-Wrangellian terrane suggest the Early Permian location of this now dispersed terrane was at 26° ± 5.3°N (Butler et al., 1997). Faunal diversity trends among brachiopods, rugose corals, and fusulinids, however, suggest placement at the latitude of the Yukon, up to 1,000 km farther north as computed from the Permian position of North America (Belasky et al., 2002). This discrepancy was in part attributed by Belasky et al. (2002) and Belasky and Stevens (2006) to cool water currents that bathed the shores of Wrangellia. These gave the faunas a more northerly character. Belasky et al. (2002) and Belasky and Stevens (2006) also estimated the longitudinal position of Wrangellia to have been 2,000–3,000 km west of the Pangaean margin of North America, based on the extreme eastern boundary of the Tethyan coral province, trend-surface analysis of faunal similarity, and relationships between all Early Permian faunas in western North America.
The purpose of this study is to document the previously unrecorded Permian colonial rugose corals from the Alaskan part of Wrangellia and to compare and contrast these faunas with those of the Pangaean craton and other terranes to better ascertain the placement of Wrangellia during the Early Permian.
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DATA
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Permian colonial corals have been recovered from three areas in the Wrangellian terrane in Alaska: (1) in the . . . [Full Text of this Article]
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